Colon cancer is the second most common forms of cancer, and is associated with a significant mortality. There is no single cause for colon cancer. The presence of benign growths in the colon, family history of colon cancer, and dietary factors are some of the factors that predispose to colon cancer. The disease is completely treatable if diagnosed early.
Researchers are now trying to develop a practical test to predict a person's risk of colon cancer by looking for a particular biological marker in the blood. If successful, the test could be broadly applied to identify those who most need to be monitored with invasive but standard colonoscopy or who should make changes in their diet or in other factors to help lower their risk of developing colon cancer.
AdvertisementIt has been suspected that genomic changes underlie cancer risk. The BRCA1 and BRCA2 genes implicated in breast and ovarian cancers are great examples, but they are applicable only to a small percentage -- less than one percent -- of women. The knowledge hasn't been translated yet into a broadly applicable way to identify individuals most at risk.
The changes associated with IGF-2 levels are linked to epigenetic mechanisms- changes in what is attached to genetic material. An epigenetic process called "imprinting normally controls the IGF-2 gene" in which the level of protein production proteins on which parent the copy came from.
For IGF-2, only the gene copy inherited from the father should be turned on, and that from the mother should be off. In about five percent to 10 percent of people, however, both copies of the gene are turned on -- a problem called loss of imprinting, leading to cancer formation.
The attempt is based on the fact that five percent to 10 percent of people have improper control of a growth-promoting gene called insulin-like growth factor 2 or IGF-2. It has been regarded that increased levels pf this protein is associated with the initiation and subsequent development of colon cancer.
If the levels of IGF 2 are found to be linked to colon cancer and a blood test is developed to assess the levels to this protein, perhaps it could lead to a less invasive option for identification of high-risk individuals. It would be as simple as measurement of cholesterol levels as a risk factor for heart disease.